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Commit d90d34bc authored by Kavya Nunna's avatar Kavya Nunna Committed by Gerrit - the friendly Code Review server
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leds: leds-pwm: Add support for blink_set callback 



Add blink_set callback to support the led blinking using
the pwm peripheral instead of the software based
blinking supported by the led framework.

Change-Id: I38f7ad5b348639830d11f42dcb960d830c1463c9
Signed-off-by: default avatarKavya Nunna <knunna@codeaurora.org>
parent 49f04345

drivers/leds/leds-pwm.c

+136 −13
Original line number Diff line number Diff line
@@ -22,12 +22,29 @@ 
#include <linux/leds_pwm.h>

#include <linux/slab.h>



#define PWM_PERIOD_DEFAULT_NS 1000000



struct pwm_setting {

	u64	period_ns;

	u64	duty_ns;

};



struct led_setting {

	u64			on_ms;

	u64			off_ms;

	enum led_brightness	brightness;

	bool			blink;

};



struct led_pwm_data {

	struct led_classdev	cdev;

	struct pwm_device	*pwm;

	struct pwm_setting	pwm_setting;

	struct led_setting	led_setting;

	unsigned int		active_low;

	unsigned int		period;

	int			duty;

	bool			blinking;

};



struct led_pwm_priv {
@@ -35,35 +52,139 @@ struct led_pwm_priv { 
	struct led_pwm_data leds[0];

};



static void __led_pwm_set(struct led_pwm_data *led_dat)

static int __led_blink_config_pwm(struct led_pwm_data *led_data)

{

	struct pwm_state pstate;

	int rc;



	pwm_get_state(led_data->pwm, &pstate);

	pstate.enabled = !!(led_data->pwm_setting.duty_ns != 0);

	pstate.period = led_data->pwm_setting.period_ns;

	pstate.duty_cycle = led_data->pwm_setting.duty_ns;

	/* Use default pattern in PWM device */

	pstate.output_pattern = NULL;



	rc = pwm_apply_state(led_data->pwm, &pstate);

	if (rc < 0)

		pr_err("Apply PWM state for %s led failed, rc=%d\n",

				led_data->cdev.name, rc);



	return rc;

}



static int led_pwm_set_blink(struct led_pwm_data *led_data)

{

	u64 on_ms, off_ms, period_ns, duty_ns;

	enum led_brightness brightness = led_data->led_setting.brightness;

	int rc = 0;



	if (led_data->led_setting.blink) {

		on_ms = led_data->led_setting.on_ms;

		off_ms = led_data->led_setting.off_ms;



		duty_ns = on_ms * NSEC_PER_MSEC;

		period_ns = (on_ms + off_ms) * NSEC_PER_MSEC;



		if (period_ns < duty_ns && duty_ns != 0)

			period_ns = duty_ns + 1;



	} else {

		/* Use initial period if no blinking is required */

		period_ns = PWM_PERIOD_DEFAULT_NS;



		duty_ns = period_ns * brightness;

		do_div(duty_ns, LED_FULL);



		if (period_ns < duty_ns && duty_ns != 0)

			period_ns = duty_ns + 1;

	}



	pr_debug("BLINK: PWM settings for %s led: period = %lluns, duty = %lluns brightness = %d\n",

			led_data->cdev.name, period_ns, duty_ns, brightness);



	led_data->pwm_setting.duty_ns = duty_ns;

	led_data->pwm_setting.period_ns = period_ns;



	rc = __led_blink_config_pwm(led_data);

	if (rc < 0) {

		pr_err("failed to config pwm for blink %s failed, rc=%d\n",

				led_data->cdev.name, rc);

		return rc;

	}



	if (led_data->led_setting.blink) {

		led_data->cdev.brightness = LED_FULL;

		led_data->blinking = true;

	} else {

		led_data->cdev.brightness = led_data->led_setting.brightness;

		led_data->blinking = false;

	}



	return rc;

}



static int led_pwm_blink_set(struct led_classdev *led_cdev,

	unsigned long *on_ms, unsigned long *off_ms)

{

	struct led_pwm_data *led_data =

		container_of(led_cdev, struct led_pwm_data, cdev);

	int rc = 0;



	if (led_data->blinking && *on_ms == led_data->led_setting.on_ms &&

				*off_ms == led_data->led_setting.off_ms) {

		pr_debug("Ignore, on/off setting is not changed: on %lums, off %lums\n",

			*on_ms, *off_ms);

		return 0;

	}



	if (*on_ms == 0) {

		led_data->led_setting.blink = false;

		led_data->led_setting.brightness = LED_OFF;

	} else if (*off_ms == 0) {

		led_data->led_setting.blink = false;

		led_data->led_setting.brightness = led_data->cdev.brightness;

	} else {

		led_data->led_setting.on_ms = *on_ms;

		led_data->led_setting.off_ms = *off_ms;

		led_data->led_setting.blink = true;

	}



	rc = led_pwm_set_blink(led_data);

	if (rc < 0)

		pr_err("blink led failed for rc=%d\n", rc);



	return rc;

}



static void __led_pwm_set(struct led_pwm_data *led_data)

{

	int new_duty = led_dat->duty;

	int new_duty = led_data->duty;



	pwm_config(led_dat->pwm, new_duty, led_dat->period);

	pwm_config(led_data->pwm, new_duty, led_data->period);



	if (new_duty == 0)

		pwm_disable(led_dat->pwm);

		pwm_disable(led_data->pwm);

	else

		pwm_enable(led_dat->pwm);

		pwm_enable(led_data->pwm);

}



static int led_pwm_set(struct led_classdev *led_cdev,

		       enum led_brightness brightness)

{

	struct led_pwm_data *led_dat =

	struct led_pwm_data *led_data =

		container_of(led_cdev, struct led_pwm_data, cdev);

	unsigned int max = led_dat->cdev.max_brightness;

	unsigned long long duty =  led_dat->period;

	unsigned int max = led_data->cdev.max_brightness;

	unsigned long long duty =  led_data->period;



	duty *= brightness;

	do_div(duty, max);



	if (led_dat->active_low)

		duty = led_dat->period - duty;

	if (led_data->active_low)

		duty = led_data->period - duty;



	led_dat->duty = duty;

	led_data->duty = duty;



	__led_pwm_set(led_dat);

	__led_pwm_set(led_data);



	return 0;

}
@@ -92,7 +213,8 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv, 
	led_data->cdev.default_trigger = led->default_trigger;

	led_data->cdev.brightness = LED_OFF;

	led_data->cdev.max_brightness = led->max_brightness;

	led_data->cdev.flags = LED_CORE_SUSPENDRESUME;

	/* Set a flag to keep the trigger always */

	led_data->cdev.flags |= LED_KEEP_TRIGGER;



	if (child)

		led_data->pwm = devm_of_pwm_get(dev, child, NULL);
@@ -107,6 +229,7 @@ static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv, 
	}



	led_data->cdev.brightness_set_blocking = led_pwm_set;

	led_data->cdev.blink_set = led_pwm_blink_set;



	/*

	 * FIXME: pwm_apply_args() should be removed when switching to the